Wireless communication system, shielded yard wireless communication system, and wireless communication device

Abstract

In a wireless communication system, wireless communication devices are disposed, each including two orthogonal antennas, a transmitter, and a receiver using rotating polarized wave having a changeable transmission frequency. Specific codes are assigned to the devices, respectively and are shared. In a first of the devices, information and a first code are superimposed on a first carrier wave. In a second of the devices, the transmitted wave is received to reproduce the information with the codes assigned to the second device and the shared code assigned to the first device. The second device transmits second information through modulation using the code thereof. Each of the first and second devices adjusts the propagation frequency for a maximum ratio in intensity of a signal reproduced with the code assigned to another device to an intensity of a signal reproduced with the code assigned to the own device.

The invention claimed is: 
     
       1. A wireless communication system comprising:
 a plurality of wireless communication devices which are separately disposed, each of wireless communication devices including two antennas having a spatially non-parallel relation with each other, a transmitter, and a receiver, the transmitter and the receiver transmitting and receiving rotating polarized waves while the transmitter and the receiver vary propagation frequencies, respectively; 
 wherein specific codes are assigned to the wireless communication devices, respectively; and 
 wherein the wireless communication devices share the specific codes respectively assigned to the wireless communication devices; 
 the wireless communication devices include a first device that superimposes first information together with the specific code of the first wireless communication device as an own device on a propagation frequency to generate and transmit a first superimposed signal as an electromagnetic wave which is a rotating polarized wave; 
 wherein the wireless communication devices include a second device that superimposes second information together with the specific code of the second wireless communication device as an own device on a propagation frequency to generate and transmit a second superimposed signal as an electromagnetic wave which is a rotating polarized wave; 
 the first device receives the first superimposed signal and the second superimposed signal as a received signal and reproduces, from the received signal, the first information with the specific code assigned to the first device as an own device and the second information with the specific code assigned to the second device as another device; 
 the second device receives the first superimposed signal and the second superimposed signal as a received signal and reproduces, from the received signal, the second information with the specific code assigned to the second device as an own device and the first information with the specific code assigned to the first device as another device; 
 wherein each of the first and second devices adjusts the propagation frequency thereof so as to have a maximum ratio of an intensity of a signal reproduced from the received signal thereof with the specific code assigned to the another device to an intensity of a signal reproduced from the received signal thereof with the specific code assigned to the own device. 
 
     
     
       2. The wireless communication system as claimed in  claim 1 , wherein the two antennas are spatially orthogonal with each other. 
     
     
       3. The wireless communication system as claimed in  claim 1 ,
 wherein the first and second devices superimpose identification codes for identifying a predetermined part within one cycles of rotation of the polarized waves on the first and second information, respectively; and 
 wherein each of the first and second devices uses a polarized direction of the rotating polarized wave to have the maximum ratio of the intensity of the signal reproduced from the received signal thereof with the specific code assigned to the another device to the intensity of the signal reproduced from the received signal thereof with the specific code assigned to the own device. 
 
     
     
       4. The wireless communication system as claimed in  claim 1 , wherein each of the first and second devices uses a propagation frequency and time in one cycle of rotation of polarized wave corresponding to the polarized direction of the rotating polarized wave to have the maximum ratio of the intensity of the signal reproduced from the received signal thereof with the specific code assigned to the another device to the intensity of the signal reproduced from the received signal thereof with the specific code assigned to the own device. 
     
     
       5. The wireless communication system as claimed in  claim 1 , wherein each of the first and second devices has a period for searching the propagation frequency which provides the maximum ratio of the intensity of the signal reproduced from the received signal thereof with the specific code assigned to the another device to the intensity of the signal reproduced from the received signal thereof with the specific code assigned to the own device and performs wireless communication using the propagation frequency obtained from a result of the searching in another period different from the period. 
     
     
       6. The wireless communication system as claimed in  claim 1 , wherein each of the first and second devices reduces a transmission power at a propagation frequency and time other than time in one cycle of rotation of polarized wave corresponding to the polarized direction of the rotating polarized wave providing the maximum ratio of the intensity of the signal reproduced from the received signal thereof with the specific code assigned to the another device to the intensity of the signal reproduced from the received signal thereof with the specific code assigned to the own device. 
     
     
       7. The wireless communication system as claimed in  claim 1 , wherein each of the first and second devices measures a value of the propagation frequency providing the maximum ratio of the intensity of the signal reproduced from the received signal thereof with the specific code assigned to the another device to the intensity of the signal reproduced from the received signal with the specific code assigned to the own device for each code and uses one of a plurality of propagation frequencies in a descending order of the ratio. 
     
     
       8. The wireless communication system as claimed in  claim 1 , wherein each of the first and second devices has a transmission frequency as the propagation frequency of the own device and a receiving frequency as the propagation frequency of the another device which are different from each other. 
     
     
       9. The wireless communication system as claimed in  claim 1 , wherein the specific codes of the first and second devices have high autocorrelation characteristics and low cross-correlation characteristics, respectively. 
     
     
       10. The wireless communication system as claimed in  claim 1 , wherein a rotating frequency is less than one tenth of the propagation frequency. 
     
     
       11. The wireless communication system as claimed in  claim 1 , wherein when the first device communicates with a third device of the wireless communication devices, the first device replaces the specific code of the another device from the specific code of the second device to the specific code of the third device, and the third device sets the specific code of the first device as the another device. 
     
     
       12. The wireless communication system as claimed in  claim 1 , further comprising:
 a shield member which separates the wireless communication devices. 
 
     
     
       13. A wireless communication device comprising:
 a transmitter, a receiver, and two antennas: 
 wherein the two antennas are spatially orthogonal with each other and shared by the transmitter and the receiver, 
 wherein the transmitter comprises: 
 an information signal generator that generates an information signal for wireless communication; 
 a transmission carrier generating circuit that generates a carrier wave; 
 a rotating polarized wave frequency cosine wave generator that generates a cosine wave; 
 a rotating polarized wave frequency sine wave generator that generates a sine wave; and 
 a first transmission code generator that generates a specific code for the wireless communication device as an own device; 
 wherein the information signal is spread using the first transmission code generator, the spread signal is superimposed on the cosine wave and the carrier wave and on the sine wave and the carrier wave to generate a first superimposed signal as an electromagnetic wave which is a rotating polarized wave, and the first superimposed signal is transmitted by the two antennas, 
 wherein the two antennas receive a second superimposed signal as an electromagnetic wave which is a rotating polarized wave, 
 wherein the receiver comprises: 
 a variable frequency local wave generator that generates a cosine wave having a same frequency as the carrier wave generated by the variable frequency transmission carrier generator; 
 a rotating polarized wave frequency cosine wave generator that generates a sine wave for the second superimposed signal; 
 a rotating polarized wave frequency sine wave generator that generates a cosine wave for the second superimposed signal; 
 a first reception code generator that generates the specific code of the own device for the receiver; 
 a second reception code generator that generates a specific code of another device for the receiver; 
 a first code circulator that circulates the specific code of the own device; 
 a second code circulator that circulates the specific code of the another device, 
 wherein the cosine wave having the same frequency as the carrier wave, the cosine wave for the second superimposed signal, and the sine wave for the second superimposed signal are removed from the second superimposed signal to generate a down-converted signal, 
 wherein the receiver further comprises: 
 an own device code demodulation result measurement circuit that measures an intensity of a received signal including the specific code of own device from a correlation calculation result of the circulated specific code of the own device and the down-converted signal; 
 another device code demodulation result measurement circuit that measures an intensity of a received signal including the specific code of the another device from a correlation calculation result of the circulated specific code of the another device and the down-converted signal, 
 wherein the transmission carrier generating circuit adjusts the frequency of the carrier wave thereof so as to have a maximum ratio of an intensity of a signal reproduced from the received signal including the specific code assigned to the another device to an intensity of a signal reproduced from the received signal with the specific code of the own device.